1. Field
The present application relates generally to the operation and design of transceivers, and more particularly, to improving the sensitivity of receivers.
2. Background
High quality signal reception is especially important for the current generation of portable devices. Typically, such devices provide multiple services, such as wide area network (WAN) communication services, wireless local area network (WLAN) communication services, and various other communication services. A device may include several transceivers to provide such communication services. Accordingly, each transceiver within a device should be carefully designed to reject interfering signals and receive desired signals with high sensitivity.
Signal interference may be especially problematic in multi-radio coexistence scenarios where, for example, a portable device includes a WAN transceiver and a WLAN transceiver. In this coexistence scenario, strong radio frequency (RF) jamming signals can appear at the input of the WAN receiver due to transmissions by the local related WAN transmitter. Furthermore, jamming signals from external transmitters may also appear at the input to the WAN receiver. Such signals may jam the WAN receiver and thus interfere with WAN signal reception.
To address this problem, a filter, such as a duplexer, is typically inserted in the receive signal path to suppress jamming signals associated with transmissions by the local related WAN transmitter or external transmitters. Unfortunately, the filter introduces an insertion loss of up to approximately 2.5 dB into the receive signal path. Thus, at times when there are no jamming signals present, the received WAN signals still experience the insertion loss of the duplexer thereby reducing the sensitivity of the WAN receiver.
Therefore, it would be desirable to have an efficient way to overcome the insertion loss of a duplexer or other filter utilized in a radio front end to improve receiver sensitivity.